1. Field of the Invention
This invention relates to low-foaming compositions which incorporate therein normally high-foaming nonionic surfactants. More specifically, this invention is directed to the reduction or suppression of foaming in compositions containing normally high-foaming nonionic surfactants.
2. Description of the Prior Art
Although detergency has been associated in the minds of many with high foam levels, in some situations foam is an objectionable feature of detergents. For example, in automatic laundry and dishwashing machines that produce a high degree of agitation, excessive foam interferes with the cleaning operation and causes overflow. Unfortunately, many surfactants, and particularly many nonionic surfactants, which are desirable for such applications are characterized by high foaming and thus by themselves are not suitable for applications such as automatic laundry and dishwashing machines. Accordingly, it is known in the prior art to mix low-foaming nonionic surfactants with the high-foaming surfactants as foam control agents.
U.S. Pat. No. 3,862,243, Bellos, discloses oxyethylated then oxybutylated alcohols having the general formula R(OEt)(OBu)OH where R is a hydrocarbon group preferably from about 6 to 22 carbon atoms. These oxyalkylated alcohols are employed as antifoamers, however, there is no mention of using these compounds as defoamers for high-foaming nonionic surfactants.
An article by Kuwamura et al, Journal American Oil Chemists Society, 48, pp. 29-34 (1971), entitled "Surface Active Block Copolymers: 1. The Preparation and Some Surface Active Properties of Block Copolymers of Tetrahydrofuran and Ethylene Oxide," discloses surface active block copolymers which are indicated as effective antifoamers for anionic detergents but inefficient for nonionic solutions.